Vulnerability valve



Jan. 10, 1950 H. w. wlsHART VULNERABILITY VALVE 2 Sheets-Sheet 1 Filed April 24, 1945 all ' INVENTOR HERBERT w wlsHART ATTORN EY Jan. l0, 1950 H. w. wlsHART VULNERABILITY VALVE 2 Sheets-Sheet 2 Filed April 24, 1943 INVENTOR HERBERT W WISHART ATTORNEY Patented Jan. l0, .-1950 zartem UNITED STATES" PATENT ori-Ica VULNERABILITY VALVE Herbert W. wishm, University city, Mo., usignor to Curtiss-Wright Corporation, a col'- poration of Delaware Application April 24, 1943, Serial No. 484,455

, from the system and hence insuring the continued normal operation of the various instrumentalities or mechanisms adapted to be actuated by the fluid in the other branches of the system.

In the present hydraulic systems for aircraft, no provision is made other than a manually operable valve for closing olf a cut off or ruptured line. When a line of such a hydraulic system is ruptured by gun nre, unless immediate steps are taken by the pilot to manually close off the branch including such line, the uid from the main reservoir will have become exhausted, thereby rendering inoperative other branches of the hydraulic system, as well as the ruptured branch. The detecting of the cut oi or ruptured part of the system' is left entirely to the alertness of the pilot. If the pilot is in combat with his airplane, he is given little time to detect this condition of his ud system. Often by the time the discovery is made, it is too late for him to operate the manual valve and the fluid fromv the main reservoir will have been lost.

One object of the invention, therefore, is to provide a valve which is so designed that it will permit normal flow of actuating fluid to and through the lines of the branch of the hydraulic system in which it is incorporated but which, in the event that a line of said branch is for any reason ruptured, will automatically isolate said branch from the fluid source and from" the other branches of the system, thereby preventing draining of the hydraulic uid of the system through the ruptured line, and hence insuring t-he continued normal flow of such fluid to and through the other branches of said system and, therefore, the normal functioning of the iluid-actuated instrumentalities of such branches.

It is another object of the invention to provide f l such a valve which will permit normal iiow of fluid therethrough, yet so constructed that the rate of this flow through the valve, if changed, will not tend to close off the same, or in other Words, to provide a valve of this type which will Y. the displacement piston.

be unaffected by line surges or changes in the rate of now through the valve.

It is another object of the invention to provide in such a valve a body of fluid usable to supply the auxiliaries serving as a part of the hydraulic system and thus a type of valve which is not dependent upon the maintenance of a solid column of iluid in the supply and return lines to and from a fluid actuator, i. e. to and from a fluid motor or other device actuated by iluid.

According to the present invention, there has been provided a valve having a displacement chamber in which there is always on tap a body4 of fluid which, when delivered to the supply line, is suiilcient in quantity to actuate any auxiliary disposed therein while the auxiliary is cut of! from the main source of fluid. A directional valve is located in the pipe line connections with the fluid actuatorand as it is turned to start the flow of uid to and from the iluid actuator, a portion of this body of iluid is delivered to the supply line. As soon as a return ilow of fluid has been initiated by the displaced portion of said body of fluid a normally closed bypass valve is open to permit fluid from the main pressure source to flow around said body of iluid directly to the auxiliary and the fluid actuator. Not until the by-pass valve has been actuated is a second valve operated to direct the return fluid from the actuator back to the lmain reservoir or fluid pressure source. Upon failure or rupture of the supply or return line to the iluid actuator, and the loss of the return flow of iiuid to the valve, the bypass valve is automatically closed, the same having been kept open by and being dependent upon the return fluid flow. The loss of fluid from' the main system in addition to the amount of fluid in the fluid supply and return lines is thus limited to the amount of iluid contained in the displacement chamber. Upon repair of the ruptured line, the automatically operable valve may be primed by` a priming means disposed between the pressure supply line and the under side of For other objects and for a better understanding of the invention, reference may be had to the followingdetailed description taken in connection with the accompanying drawing, in which Fig. 1 is a more or less diagrammatic view oi' a hydraulic system suchv as used on airplanes and embodying the vulnerability valve of the present invention, the valve being shown in the perspective and broken'away to show the vital parts thereof; v

3 Fig. 2 is a cross-sectional view, in elevation, taken through the sequencing chamber of the valve and along the line 2-2 of Fig. l.

, priming mechanism.

Fig. is a cross-sectional view in another plane taken through the return flow fitting of the valve l and showing the restricter valve therein and along the line 5-5 of Fig. 3.

Referring now particularly to Figs. 1 and 2, there is shown a fluid pressure source or reseri voir II) adapted to deliver fluid under pressure through a pipe line I I to a vulnerability valve I2 of the present invention. The fluid leaves the vulnerability valve through a supply line I3, and is directed to one side or another of a fluid actuator I4 depending upon the position to one side or another of neutral of a four-way or directional valve I5. With the directional valve I5 set as 1 shown in Fig. 1, fluid will continue from supply line I3 to an auxiliary I6 which, as shown, may

be a hook-up latch for landing gear of an airplane and thence after operating the same throughline I1 to side I8 of the iluid actuator I4.

The fluid actuator I4 includes a piston I9 which divides the side I8 of the fluid actuator from a side from which fluid will be forced through a return pipe line 2I for delivery to the valve I2.

` After the fluid being returned through the pipe line 2I operates the valve I2, it is returned to the 1 fluid reservoir I0 through a main return pipe 22.

The valve I2 includes a housing 23 in which is disposed a displacement chamber 24 and a sequence valve chamber 25. Within the displacement chamber 24, there is disposed a piston 26 adapted to be acted upon by fluid entering the valve I2 from the fluid pressure source I0 by way of the pipe II. The entry of this fluid ls through a fitting 21 which is screwed into the chamber 24 to close one end thereof. Fitting 21 is provided with a sealing ring 28 and the lower end thereof serves as a stop against which the piston 26 is arrested in its upward movement.

The lower end of the chamber 24 ls closed by a fitting 30 similar to fitting 21 and on which is supported a compression spring 3| adapted to normally force the piston 26 up against the iltl ting 21. With fluid being disposed on both sides of the piston 26, the piston 26 would be balanced except for the action of the spring 3|. It will be more apparent as to how the fluid on the lower side of the piston 26 is obtained as the description proceeds.

Within the sequence valve chamber 25, there is provided a poppet valve unit 32. This unit ini extend through a central opening in the bottom cludes a main body member 33 on which there is threaded a closure cap 34 to provide a closed chamber 35. Within this chamber 35 there is a poppet valve element 36 adapted to seat against i a seat portion 31 of the body 33 to control the flow of fluid from the chamber 35 through a passageway 38 which extends downwardly and laterally as indicated at 39, for delivery of fluid to a downagainst the cap 32 to normally force the poppet valve 36 toward its seat portion 31. The poppet valve 36 also has a stem portion 42 adapted to of the body member for contact with an operating plunger 43.

Communicating between the displacement chamber 24 at the upper side of the piston 28 and the chamber 35 Within the body member and located partly in the housing 23 and partly in the main body member 33, is a. cross passage 45. Through this passage, fluid under pressure is passed to lill the chamber 35 and to further lock the poppet valve against its seat portion 31, as shown in Fig. 2, so as to positively seal oil the fluid in the chamber 35 from the passages 38, 39, and 40. As long as the poppet valve 36 is closed, fluid from the line Il will not ow through the valve I2.

As the four-way valve I5 ls turned to effect actuation of the fluid actuator I4, fluid will be delivered to the supply line I3 from the displacement chamber 24 under action of the fluid pressure upon the piston 26. The amount of uid in the chamber 24 is sulcient to illl the auxiliary I6 for its actuation and to cause the delivery of the uid therefrom through pipe I1 to the side I8 of the fluid actuator. As soon as this takes place the piston I9 within the fluid actuator I4 is moved downwardly so as to force fluid from the side 20 thereof through the return line 2| and valve I5 to the valve I 2. The return pipe 2I enters the valve I2 at the side of the same and fluid therefrom enters an inlet opening 48, Fig. 2, for delivery to the sequencing valve chamber 25. Prior to the admission of the supply fluid through the opening 48, the plunger 43 is disposed in its lowered position, as shown in Fig. 2, and against a seat 56 provided by an outlet iltting 49 which is screwed into the housing 23 in much the same manner in which fittings 21 and 30 are screwed into the housing 23. The plunger 43 has in its bottom thereof, a return pipe closure valve element which is connected to the plunger 43 to have lost motion with respect thereto in an opening 5I formed in a cup-shaped fitting 52 threadingly connected with the plunger 43. Fluid entering the opening 48 passes through openings 53 in the fitting 49, openings 54 in the fitting 52, and openings 55 in the return fluid valve element 50. Pressure is immediately built up against the return fluid valve 50 to temporarily maintain the same against the seat 56 so as to temporarily prevent the iiow of fluid through an outlet 51 in the fitting. Also a spring 58 extending between the valve element 50 and the plunger element 43 aid to maintain the valve 58 against the seat 56.

Fluid pressure is thus allowed to build up against the plunger element 43 so that it is moved upwardly against the action of a spring 68 to contact the stem 42 of the poppet valve element 36. This upward movement of the plunger 43 continues until the poppet valve 36 is lifted olf its seat 31 to the position shown in Fig. 1, whereupon fluid on the upper side of the displacement piston 26 will be delivered through passage 45 to the vertically extending bypass 40, which extends downwardly to the bottom of the housing for connection with a lateral inlet opening 6I to chamber 24. In this manner iluid is bypassed about the piston 26 and a continuous ow from the fluid source I0 will be effected through the valve I2 as long as the four-way valve I5 is in position to cause actuation of the iluld actuator I4. As soon as the fluid pressure at the lower side of the piston 26 approaches the pressure at the upper side of the piston, the latter will be returned by spring 3I to its initial position, therev by replacing the fluid in the chamber 24 which was initially forced from the same to start the actuation of the fluid actuator. When the lost motion between fitting 52 and valve element 5f) has been taken up during upward movement of plunger 43, valve element 50 is lifted to permit a return flow from opening v48 through passage 51 and pipe 22 to the pressure source I0.

Should a rupture occur in any of the linesof the fluid system, such as due to either of the lines I3 and 2| being shot off, the return flow of fluid through the pipe line 2l is lost and fluid serving to hold the plunger 43 in its up positionv against the poppet valve stem 42 is lost. The plunger 43 will then move downward, the space above the plunger being capable of breathing through an air opening 63. The poppet valve 36 will thereupon be closed and fluid flow through the by-pass 40 is immediately disrupted, whereby, after an emptying of chamber 24, the fluid supply line I3 is positively closed off. As the plunger 43 with the return flow valve 50 moves downwardly, the return valve will finally contact with its seat portion 56 to thereby positively close off the flow to the return line 22. The valve will have in this manner isolated from main pressure source I0 the branch of the system which includes the ruptured line. Draining of the actuating fluid from the entire hydraulic system through the ruptured line being thus prevented, adequate fluid will remain in the system to feed the lines of all of the other branches. Except for the branch having the ruptured line, therefore, the entire system will continue to function in the normal manner.

Referring now more particularly to Figs. 3. 4, and 5, there is shown a modified form of the valve. The general operation of the valve is the same as the valve just described, but there are features in it which render the valve more posi- Y tive in its actuation and easier to construct. The description thereof will thus be limited to the features of this valve which are different from the valve just described. It has a plunger element formed to include a return fluid valve element 66 of such construction that its operating spring 61 is disposed about the valve element 66 rather than within an opening in the same. As the plunger 65 is moved upwardly, the valve 66 is maintained on its seat 68 only by action of fluid pressure acting within a hollow chamber 69 rather than by action of its spring. The plunger element 65 moves upwardly without the valve element 66 until such time as its shoulder 10 positively engages a shoulder 1I on the valve element 66, at which time the valve element 66 will be bodily moved upwardly with the plunger. This opening of the valve B6 takes place only after poppet valve 36 has been opened.

With such an arrangement as shown by this form of the invention, the valve element 66 can not be closed until after the poppet valve 36 is closed. This is because of the action of spring 61 which positively maintains the valve element 66 collapsed within the plunger 65.

In order to prevent a sudden outflow of fluid to the return pipe line 22 and in that way tending to drop the plunger so as to close the poppet valve 36, there is provided a restrictor element 14 in the fitting 49. This restrictor element will tend to throttle all fluid leaving the valve and in that way will prevent the plunger from suddenly permitting the valve 36 to close off the supply flow of fluid through the valve. This element will also serve to restrict any effects from back pressure which might occur in line 22.

As seen more readily in Fig. 4, there is shown adapted to seat against a valve `seat 19. This l priming means is in communication -with the v fluid pressure source I 0 and as the plunger 16 is depressed, fluid will be taken from the fluid pressure source and be delivered through an opening to a lateral extending opening 8| which is in communication with a vertically extending bypass 8'2 which delivers the fluid to an opening 83 which is in communication with the displacement chamber 84. This priming action will continue until sufllcient fluidhas been built up in the fluid system and within the chamber 84 so as to return its piston 85 to the upper portion of the chamber 84 and against its fitting 85.

It should now be apparent that there has been provided a valve arrangement particularly adaptable for use in aircraft which will serve to permit ow as long as the branch of the system with which the valve is associated has not been ruptured but will automatically cut off the flow to the said section, should the supply and return lines be shot off or ruptured. It should also be apparent that there has been provided with this type of valve a displacement chamber suitable to contain sufficient amount of fluid to flll the auxiliary I6 and to establish a continuous flow of fluid to the fluid actuator I4, and also that there has been provided such a valve arrangement whereby .the changes in the rate of flow, as established by the fluid pressure source, will not affect the operation of the valve and that the action to close off the valve is positive and unaffected by the fluid pressure source.

While various changes may be made in the detailed construction, it shall be understood that such changes shall be within the spirit and scope of the present invention as dened by the appended claims.

I claim as my invention:

1. In combination, a fluid pressure source, a double acting fluid motor, a safety valve connected by incoming and return lines to the fluid pressure source and to the double acting fluid motor by means of pipe lines which are subject to rupture, a fluid actuated auxiliary connected in one of the lines leading from said safety valve to said motor, a directional valve in the pipe lines to determine the direction of flow to and from the fluid motor, said safety valve having means for maintaining a body of fluid of sufficient quantity and operable by the incoming fluid to actuate the fluid actuated auxiliary, and means dependent upon the return fluid flow from the fluid motor for bypassing the flow of incoming fluid around the maintaining means to continue its flow to the auxiliary and to the fluid motor, and, after this flow has been established, for directing the return fluid to the pressure source return line.

2. In a vulnerability valve, a valve housing having a displacement chamber with a piston therein and a sequence valve chamber, bypass means for circumventing fluid about the displacement piston for delivery to an outlet in the valve housing, said bypass means including a poppet valve located in the sequence valve chamber, a plunger in the sequence valve chamber for operating the poppet valve, said plunger being adapted to be operated by fluid flow being returned to the valve, a return fluid valve connected to the plunger to have lost motion movement with respect thereto whereby the return fluid valve may-remain on its seat during a part of the stroke of the plunger and will be opened after the by-pass poppet valve has been opened,v said iluid return valve when open putting return uld in communication with an outlet opening of the valve, whereby the bypass valve and fluid return valves are both operated by fluid return flow and in a sequential manner.`

3. In a vulnerability valve, a iluid housing having a displacement chamber with a piston therein and a sequence chamber extending` therethrough, a pair of passageways extending between the two chambers to bypass fluid about the piston, said 'passageways entering the chambers at different levels, a container with a poppet valve therein mountable ,as a unit in one end of the sequence chamber and having openings therein controllable by the poppet valve and adapted to register with the respective passageway means vto control the flow of iluid therethrough, a

plunger in the sequence chamber adapted to be moved by return fluid ow to the valve, said poppet y'valve extending from its container` to be operated by the plunger, a return fluid outlet valve adapted to be seated in an outlet fitting closing the opposite end of the sequence chamber, and 10st motion connection means for connecting the return fluid outlet valve to the plunger so as to permit operation of the poppet valve prior to the operation of the return iluid outlet valve, said plunger thereby serving to operate both valves and in a sequential manner.

4. In a vulnerability valve, a fluid housing having a displacement chamber with a piston therein and a sequence chamber, passageway means in the housing extending between the two chambers to bypass fluid about the piston to establish continuous flow through the valve, poppet valve means in the sequence chamber to control the flow of iluid through the passageway means, plunger means in the sequence chamber spaced from said poppet valve means, adapted to be acted upon by return fluid and arranged to operate the poppet valve means only after it has moved a predetermined distance toward said poppet valve means, a return iluid outlet valve connected to the plunger for lost motion movement with respect thereto,`biasing means between the return valve and the plunger tending to maintain the valve collapsed Within the plunger, passage means Within the return valve to permit the retaining of the same on its seat by fluid acting upon it and against the action of the biasing means to cause lost motion to be taken up and the operation f the bypass poppet valve before opening of the return valve to divert the return flow through its outlet opening, said biasing means, by virtue of its tendency to collapse the return valve within the plunger in a direction opposite to that in which the return valve must be moved to be seated preventing closure of the return outlet opening before closure of the bypass poppet valve.

5. An automatic control device for a fluidoperated system which includes a source of iluid under pressure, a iluid motor, and supply and return lines connecting said motor to said source,

. said automatic control device having a passage through which fluid traversing the supply line may flow and a second passage through which fluid traversing the return line may flow, a valve for closing said rst mentioned passage, a second valve for closing said second passage, resilient means for normally holding said valves closed,

8 a piston whicli--ls-movable in response to the duid pressure in said supply line upstream from said first mentioned valve toeilect an initial displacement of fluid in said return line, a second piston carrying one of said valves and having a lostmotion connection with the otherand being movable in response tosuch displacement to open said 1 valves successively against the action of said resili'ent means to thereby first permit iluid to flow through said vfirst mentioned passage to said motor and secondly to permit fluid to4 flow through said second passage to said source, and

resilient means for restoring said first mentioned piston to its original position after said valves have been opened in the manner described, said' valves being held open thereafter by the flow of fluid through said second passage and being closed automatically by said first mentioned resilient means in the event of an interruption in such flow.

6. An automatic control device for a fluidoperated system having supply and return lines, said vautomatic control device having a passage through which fluid traversing the supply line may flow and a second passage through which fluid traversing the return line may flow, avalve for closing said rst mentioned passage, a second valve for closing said second passage, resilient means for normally holding said valves closed, a piston which is movable in response to the fluid pressure in said supply line upstream from said rst mentioned valve to eiect an initial displacement of uid downstream from said first valve, a second piston carrying one of said valves and having a lost-motion connection with the other and being movable in response to such displacement to open said valves successively against the action of said resilient means to thereby rst permit uid to flow through said rst mentioned passage andsecondly to permit fluid to flovv4 through said second passage, and resilient means for restoring said rst mentioned piston to its original position after said valves have been opened in the manner described, said valves being held open thereafter by the flow of fluid through said second passage and being closed automatically by said rst mentioned resilient means in the event of an interruption in such flow.

7. In an automatic valve, a body having a displacement chamber communicating at its opposite -ends with a pressure inlet port and a pressure outlet port; a piston movable in said displacement chamber upon entry of fluid from said pressure inlet port into said chamber to displace chamber iluid through the pressure outlet port; a by-passage around said piston and communicating with said pressure inlet and outlet ports; a return passage communicating at its opposite ends with a return inlet port and a return outlet port; a poppet valve seat in each of said passages; a poppet valve for closing upon the valve seat in the by-passage and opening in a direction opposite to the normal direction of ilow through the by-passage; an operating chamber in said return passage adjacent the valve seat therein; a plunger arranged for movement in said operating chamber, in response to fluid pressure in the return passage, in the direction of opening movement of said poppet valve; an opening between said operating chamber and said by-passage; a stem in said opening substantially aligned axially with said poppet valve and plunger, said stem being movable by said plunger to open said poppet valve; said plunger having associated therewith a valve face for closing upon the valve seat in the return passage; and resilient means acting upon said plunger and poppet valve to retain them in their valve closing positions in the absence of fluid pressure in the return passage.

8. In an automatic valve, a body having a displacement chamber communicating at its opposite ends with a pressure inlet portl and a pressure outlet port; a piston movable in said displacement chamber upon entry of fluid from said pressure inlet port to displace chamber fluid through the pressure outlet port; a by-passage around said piston and communicating with said pressure inlet and outlet ports; a return passage communicating at its opposite ends with a return inlet port 'and a return outlet port; a poppet valve seat', in each of said passages, said valve seats being substantialltr aligned axially and being adapted to seat valves that are arranged to open in the same direction; an opening in a wall of the body separating said passages; and valve means for closing upon said valve seats and including a l valve operating member extending through and movable axially in said opening, said valve means being operable to open from said valve seats in responseto ii'uid pressure in the return passage.

9. In an automatic valve, a body having a displacement chamber communicating at its opposite ends with a pressure inlet port and a pressure outlet port; a piston movable in said displacement chamber upon entry of iluid into the latter from the pressure inlet port to displace chamber fluid through the pressure outlet port; a bypassage around said piston and communicating with said pressure inlet and outlet ports; a return passage communicating at its opposite ends with a return inlet port and a return outlet port; an operating chamber communicating with said return passage; a plunger in said operating chamber movable in one direction therein in response to pressure in the return passage; each of said pasages having a poppet valve seat substantially aligned axially with said plunger; a poppet valve for closing upon each of said seats, said poppet valves both opening from their seats in said one direction; means for opening the by-passage valve upon movement of said plunger in said one direction comprising a stem extending through a wall which separates said passages; a play connection between the plunger and the return passage valve, whereby the latter will open later and close earlier than the by-passage valve; and

r Number resilient means for biasing the valves to closed position.

10. In an automatic valve, a body having a displacement chamber communicating at its opposite ends with a pressure inlet port and a pressure outlet port; a piston movable in said displacement chamber upon entry of uid into the latter from the pressure inlet port to displace chamber uid through the pressure outlet port; a by-passage around said piston and communicating with said pressure inlet and outlet ports; a return passage communicating at its opposite ends with a return inlet port and a return outlet port; an operating chamber communicating with said return passage; a plunger in said operating chamber movable in one direction therein in response to pressure in the return passage; each of said passages having a poppet valve seat substantially aligned axially with said plunger; a poppet valve for closing against the valve seat in the return passage, said valve having a limited axial movement in a valve guide chamber formed within said plunger; spring means in said valve chamber biasing said valve to the limit of its movement relative to the plunger in the direction toward the valve seat in the return passage; a second poppet valve for closing upon the valve seat in the by-passage, means comprising a valve stem for opening said second valve upon movement of said plunger in said one direction, and spring means in said operating chamber for biasing the plunger in the opposite direction to seat the second valve in the absence of fluid pressure in the return passage.

HERBERT W. WISHART.

REFERENCES CITED The following references are of record in the ille of this patent:

UNITED STATES PATENTS Name Date Hauser Sept. 16, 1930 Perkins Nov. 18, 1941 Field Sept. 30, 1947 

